Japan's Prime Minister Shinzo Abe has launched work for India's first high-speed train in Prime Minister Narendra Modi's native state of Gujarat.
Mostly funded by a $17bn loan from Japan, the bullet train will run between Ahmedabad city and Mumbai.
It is expected to cut the 500km journey time down to three hours from the current eight.
Prime Minister Abe is making a two-day visit to India, a close ally of Japan.